NOP2 and Williams syndrome: Numerous genetic birth defects and developmental defects involve mutations in RNA modifying enzymes, such as Cri du chat syndrome (NSUN1) [18], Dubowitz syndrome (NSUN2) [19], William-Beuren syndrome (Williams-Beuren syndrome chromosome region 22/22, WBSCR20/22, and NSUN5) [20], and Hutchinson-Gilford progeria syndrome (N-Acetyltransferase 10, NAT10) [21, 22].